Striated and powerful but the cells are short and

  • No School
  • AA 1
  • 14

This preview shows page 2 - 4 out of 14 pages.

striated and powerful, but the cells are short and branched, not fused together in multi-nuclei fibers but "zipped" together with special connections (intercalated discs) that may be visible under the microscope; unlike skeletal muscles, cardiac muscles can contract with a set rhythm, as would be useful in a blood-pumping organ, and are not generally under any kind of conscious control. Smooth muscle cells are not striated, often short, single cells with points at each end; compared to the other muscle types, they are weaker, use less energy, but are almost tireless, often forming sheets or tube linings in organs that need to move materials along. They are not usually under conscious control. Nervous Tissue : Distinct features and functions: only the cells in nervous tissues can carry electrochemical messages called impulses, which allow us to process reflex, memory, and understanding in our spinal cords and brain; some nervous tissue can convert environmental information into those messages - they function as receptors for our senses, in sense organs. Elsewhere, the "wiring" of the system is usually too fine to be visible under a microscope. Reproductive / Germ / Stem Tissue : Distinct features and functions: cells in this tissue, which is known by several names, have the ability to take normal body-type cells, each of which contain two sets of chromosomes (one from each parent), and through a special cell division process called meiosis produce gametes, either sperm or egg cells, which contain only single sets of chromosomes and can be used to produce offspring. Sperm and egg cells are considered types of reproductive tissue. ANIMAL TISSUES In animals, organs are composed of varying combinations of four basic tissue types -- epithelial tissue, connective tissue, muscle tissue and nervous tissue. Each of these tissues has distinctive structural features and specific functions which are again combined to produce 2
Image of page 2

Subscribe to view the full document.

functioning organs. The various tissues will be examined and their organization into one specific organ will be studied. A. Basic Tissue Types Epithelial Tissue: Epithelial tissue forms the covering or lining of free body surfaces, both internal and external. For example, the outer layer of the skin is formed from epithelial tissue as are the inner linings of the digestive tract and blood vessels. As a group, epithelial tissues perform a variety of functions, including protection, absorption, excretion, secretion and lubrication . Classification of Epithelial Tissue : The cells of the epithelial tissue are tightly packed and rest on a thin basement membrane (Figure 3). The free surface of the epithelium is exposed to air or fluid. No blood vessels are present. Epithelial tissues are classified according to the shape of the component cells and the arrangement of these cells into one or more layers. The shapes of the cells may be (Figure 3): squamous -- flat, scale-like cells (“fried-egg” appearance).
Image of page 3
Image of page 4
  • Fall '19

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes